I know this isn't the most appropriate place but it is the most popular community that might have an opinion so here I am..
The black nail polish I have kinda sucks. It starts to crack after a couple days and it's finished after a week. My wife's non-black polish lasts like 2 weeks or so and still looks great.
Where is it cracking and do you use a base and top coat? I have found that application has more to do with longevity than brand. Also, do you push the cuticles back and put nail polish remover on your nail before you polish to remove any oil?
I would try these things and see if things improve. Make sure to top coat around the tip of the nail and quickly remove any overbrushing on the skin so it doesn’t peel from there.